An internal combustion engine of a motor vehicle requires oxygen for combustion of fuel. Therefore, oxygen-containing air from the environment is taken in and purified by means of an air filter. An air filter for a motor vehicle has, for example, a filter body and a separating chamber. The filter body comprises, for example, a filter nonwoven for binding the particles contained in the air. In the separating chamber dirt is collected that is filtered by preseparation from the air and that is not adhering to the filter body.
The separating chamber can be coupled with an exhaust gas ejector in the exhaust gas manifold of the motor vehicle in order to remove the dirt from the separating chamber. The exhaust gas ejector generates underpressure or partial vacuum by means of which the dirt is sucked from the separating chamber and then ejected. Regularly, a non-return valve is arranged between the exhaust gas ejector and the separating chamber because, in some operating states of the internal combustion engine, overpressure is generated in the exhaust gas ejector and this may cause that hot exhaust gas is forced into the air filter. The temperature of the hot exhaust gases can reach approximately 500 degrees Celsius and can damage the air filter, in particular the filter body, of the air filter.